(Not Applicable)
1. Field of the Invention
The present invention relates to an apparatus and method for applying component parts of a sealant which when mixed transforms from a fluidic state to a non-fluidic state. In particular but not exclusively, the present invention is directed to an apparatus and process in which sealant components are mixed prior to being applied to biological tissue to effect hemostasis or achieve other therapeutic results.
2. Description of Related Art Including Information Disclosed under 37 CFR 1.97 and 37 CFR 1.98
Use of tissue sealants and other biological materials is an important emerging surgical technique, well adapted for the operating room or field environments such as the doctor""s office or mobile medical units. In addition, the application of such sealants while performing or as necessary to perform minimimally invasive surgery reduces or eliminated the traditional problems associated with more invasive types of procedures. Preferred sealants include fibrin sealants which are formed from blood plasma components and comprise, on the one hand, a first component containing fibrinogen and Factor XIII and on the other hand a second component which usually includes thrombin, and calcium ions.
The fibrinogen is capable of a polymerizing and being cross-linked to form a solid fibrin clot when the components are mixed. The necessary additional factors to simulate relevant portions of the natural blood coagulation cascade are suitably distributed between the fibrinogen and thrombin components.
High levels of protection against transmission of infections or induction of immunological reactions can be assured by using an autologous or single-donor source for both components. Such sealants are highly effective, are biologically degraded without residue and may promote wound healing.
Depending upon the potency of the particular formulations employed, coagulation of the sealant may take place very rapidly, yielding a gel within perhaps 10 or 20 seconds after mixing of the two components. Though often very desirable for surgical reasons, such fast-acting properties present potential problems of fouling or clogging. These problems must be overcome in devising suitable applicators, and methods of application.
A popular manually operable applicator for such two-component sealants employs a dual syringe construction wherein two syringes, connected by a yolce, each provide a reservoir for one of the components. In most prior devices, the sealant components are discharged in separate streams and mixed externally of the applicator. Such applicators are similar in principle to household epoxy glue applicators commonly available in hardware stores. Achieving effective mixing externally of the applicator is problematic.
In U.S. Pat. No. 5,266,877, and the above applications, the present inventor teaches various constructions of a dual syringe applicator wherein the fluid sealant components are mixed internally.
Antanavich et al. U.S. Pat. No. 5,585,007, whose disclosure and references are hereby incorporated herein by reference thereto, provides an extensive discussion of the literature relating to fibrinogen sealant preparation (column 1, line 20 to column 4, line 62) and applicators column 4 line 62 to column 5, line 14), as well as a bibliography, (columns 6-10) and is a helpful guide to the teachings of prior workers in the field.
Though a superior quality sealant can be obtained, a difficulty with internal mixing is that the coagulating nature of the sealants causes the discharge opening or openings of an application device to become clogged so that flow out of the applicator slows down or stops.
While the above-referenced copending applications disclose effective clearing methods, difficulties may occur if the mixing pathway to be cleared has an extended length such as might be required to reach an unexposed location or work site.
There is accordingly a need for a sealant applicator and method that can be used to reach an unexposed location and that is capable of being rapidly unclogged without disassembly of the applicator.
The present invention solves this problem by providing an applicator tip comprising a mixing chamber communicating with two or more reservoirs which can effectively deliver mixed multiple sealant components to a remote work area and is capable of being unclogged without removing or relocating the applicator tip or by dispersing unwanted clots into the application environment.
The present invention also assures that an effective sealant composition reaches the area of application because the sealant components are actively mixed in close proximity to the applicator outlet while also providing for means of removal of coagulated sealant from the applicator tip.
Preferably, although not necessarily, the sealant is a biological sealant, for example a tissue adhesive, and the area of application is a biological tissue subject to surgery. The sealant components can comprise a first, structural component capable of gelling, and preferably of solidification and a second, activation component which activates such gelling and, optionally, solidification. More preferably, the sealant is a tissue sealant and the first component comprises fibrinogen and the second component comprises, or can generate a fibrinogen activator, especially thrombin or an equivalent thereof.
The invention also provides a novel surgical method of applying sealant to unexposed or internal biological surfaces, e.g. human or animal anatomical surfaces, that are accessible to a remote application devices, such as the ones disclosed in aforementioned patent applications. The use of a remote mixing chamber, which receives a flow of multiple sealant components and mixes the sealant components at the distal end of the applicator, allows the distal end of the applicator to apply a mixed sealant a work site.